Publication: Evaluación geohidrológica del sector costero ubicado entre Bahía Bustamante y Camarones, Chubut, Argentina
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Asociación Geológica Argentina
Abstract
En zonas costeras áridas, el agua subterránea tiende a ser de características salobres y los cordones litorales suelen ser sitios donde se generan lentes de agua dulce. A partir del estudio hidrogeológico y geoeléctrico del área costera entre Bahía Bustamante y Camarones, este trabajo analizó la factibilidad de reservorios de lentes de agua dulce en cordones litorales que existen en esa zona. El trabajo incluyó además un relevamiento regional de fuentes de agua (conductividad eléctrica y nivel freático). Sobre los cordones litorales pleistocenos y holocenos se realizaron sondeos eléctricos verticales y calicatas para la descripción de suelos y ensayos de infiltración. Los estudios efectuados indican que los cordones holocenos presentan condiciones hidrolitológicas más propicias que los pleistocenos para la infiltración de agua de lluvia y su almacenamiento en forma de lente de agua dulce. No obstante, no se ha identificado la presencia de lentes de agua dulce en ninguno de los cordones litorales explorados. El desarrollo de suelos con horizontes argílicos y cálcicos es probablemente el principal motivo por el cual los cordones pleistocenos no constituyen zonas de recarga preferenciales. Por su parte, si bien los cordones holocenos presentan características favorables para alojar lentes de agua dulce, el reducido desarrollo areal de estas geoformas podría ser un condicionante para el desarrollo de reservorios de agua dulce dentro de estas geoformas. Los resultados obtenidos evidencian la necesidad de realizar estudios hidrogeológicos de mayor detalle que permitan verificar de manera más determinante el funcionamiento geohidrológico del área.
In arid coastal areas, groundwater is usually brackish and coastal ridges are often sites where freshwater lenses are generated. The purpose of the study was to explore hydrogeologically and geoelectrically the area between Bahía Bustamante and Camarones in order to evaluate the feasibility of the sequence of coastal ridges in that area to constitute freshwater lens reservoirs. A regional water source survey was carried out, where the electrical conductivity of the water and the phreatic level were measured. On the Pleistocene and Holocene littoral ridges, vertical electrical soundings and soil description and infiltration tests were carried out. The studies carried out indicate that the Holocene ridges present more favorable conditions for rainwater infiltration and its storage in the form of freshwater lenses than the Pleistocene ones. However, the presence of freshwater lenses has not been identified in any of the coastal ridges explored. The development of soils with argillic and calcic horizons is probably the main reason why the Pleistocene cords do not constitute preferential recharge zones. Although the Holocene cords present favorable characteristics to host freshwater lenses, the reduced areal development of these geoforms could be a conditioning factor for their development. The results obtained show the need to carry out more detailed hydrogeological studies to verify the geohydrological functioning of the area.
In arid coastal areas, groundwater is usually brackish and coastal ridges are often sites where freshwater lenses are generated. The purpose of the study was to explore hydrogeologically and geoelectrically the area between Bahía Bustamante and Camarones in order to evaluate the feasibility of the sequence of coastal ridges in that area to constitute freshwater lens reservoirs. A regional water source survey was carried out, where the electrical conductivity of the water and the phreatic level were measured. On the Pleistocene and Holocene littoral ridges, vertical electrical soundings and soil description and infiltration tests were carried out. The studies carried out indicate that the Holocene ridges present more favorable conditions for rainwater infiltration and its storage in the form of freshwater lenses than the Pleistocene ones. However, the presence of freshwater lenses has not been identified in any of the coastal ridges explored. The development of soils with argillic and calcic horizons is probably the main reason why the Pleistocene cords do not constitute preferential recharge zones. Although the Holocene cords present favorable characteristics to host freshwater lenses, the reduced areal development of these geoforms could be a conditioning factor for their development. The results obtained show the need to carry out more detailed hydrogeological studies to verify the geohydrological functioning of the area.